Does walking exercise improve bone mineral density of young obese and thin women?

Abstract

The purpose of the present study was to examine the effect of walking program on BMD in order to prevent bone loss among sedentary obese and thin young women. Forty untrained obese (n=20) and thin (n=20) women, 20-25 years, volunteered to participate in this study, then participants were pairwise BMI-matched and randomly assigned to two exercise (obese=10, thin=10) and two control (obese=10, thin=10) groups. Before and after the training program both groups had anthropometric measurements and blood analysis. Bone mass density also was evaluated by using dual-energy X-ray absorptiometry (DXA) .Each walking session was 30 min walking between 50-75% of maximal age adjusted heart rate, 3 days per week for 2 months. After 2 months, exercise groups had no significant effect on BMD at weight-bearing sites in the spine (L2-L4) and hip(p>0.05). However exercise groups experienced slightly increased in BMD at both region, while the control groups did not. Also no significant change was observed in blood samples in either group (p>0.05). Percent body fat, fat mass and lean mass were affected positively by the exercise program compared with control groups (all p = 0.000). This study demonstrated that walking exercise reduce the risk of bone loss in young women. However further studies are needed to evaluate the efficacy of walking exercise on bone quality and the risk of bone loss as an exercise-related effect in different obese and thin groups of women.

Keywords: Bone Mass Density, Bone Loss, Walking Exercise, Obese and Thin Women.